Resheathing tool

ABSTRACT

The resheathing tool includes a flexible tubular body with a wall, an inner bore, and an aperture formed in the wall. The tool can be used to facilitate the unsheathing of the vasoocclusive device from the reloadable slotted introducer sheath by threading a proximal portion of the sheath out the aperture of the tool while sliding the vasoocclusive device distally through the sheath. The tool facilitates resheathing of the vasoocclusive device by introducing the vasoocclusive device through the slot of a reloadable slotted introducer sheath into the sheath by threading the reloadable slotted introducer sheath through the aperture and into the inner bore of the tool while threading the vasoocclusive device through the inner bore of the tool. At the same time, the resheathing tool prevents the elongated vasoocclusive device from moving out of the reloadable slotted introducer sheath through the slot.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to devices for interventionaltherapeutic treatment or vascular surgery for treatment of defects inthe vasculature, and more particularly concerns a system and method fordelivering intravascular interventional devices, such as for treatmentof aneurysms.

2. General Background and State of the Art

Vascular interventional devices such as vasoocclusive devices aretypically placed within the vasculature of the human body by use of acatheter. Vascular interventional devices such as stents can be placedwithin an occluded vessel to facilitate blood flow through the vessel,and vasoocclusive devices are typically either placed within a bloodvessel to block the flow of blood through a vessel making up thatportion of the vasculature by the formation of an embolus, or are placedwithin an aneurysm stemming from the vessel to form such an emboluswithin the aneurysm. Vasoocclusive devices used for these procedures canhave a wide variety of configurations, and aneurysms have been treatedwith external surgically placed clips, detachable vasoocclusive balloonsand embolus generating vasoocclusive devices such as one or morevasoocclusive or embolic coils.

The delivery of such vasoocclusive devices has typically beenaccomplished by a variety of means, including via a catheter in whichthe device is pushed through an opening at the distal end of thecatheter by an elongated flexible pusher member to deploy the device.The vasoocclusive devices can be produced in such a way that they willpass through the lumen of a catheter in a linear shape and take on acomplex shape as originally formed after being deployed into the area ofinterest, such as in an aneurysm.

Detachable vasoocclusive devices are typically embolic coils fixed to adistal end of a flexible pusher member for delivery of the emboliccoils, and may be detached mechanically, electrically or by some othermeans from the flexible pusher member at the target location. Thedetachable embolic coils can be delivered to the target location anddetached if correctly sized and positioned, or the embolic coils may bewithdrawn without being detached if the coils are not correctly sized,if the coils are not correctly positioned, or if the microcatheterpositioning is lost. Some available vasoocclusive devices are not reusedduring a patient procedure if they are removed during the procedure, dueto the inability to reload the device into the microcatheter. It istherefore desirable to provide a system and method for reusingvasoocclusive devices during a clinical procedure after removal from amicrocatheter introducer.

One such system and method allowing the reuse of vasoocclusive devicesafter removal from a microcatheter introducer during a clinicalprocedure provides for an introducer sheath for a therapeuticvasoocclusive device which includes an assembly of a flexible pushermember and an embolic coil. The introducer sheath is formed from ahollow, elongated tubular member, and includes a longitudinal slotformed in the upper wall of the introducer sheath and extending thelength, or majority of the length, of elongated tubular member. The slotpermits introduction of the vasoocclusive device into the interiorchannel of the introducer sheath, and permits the introducer sheath torelease the vasoocclusive device for introduction into a microcatheter,for deployment during a clinical procedure. The vasoocclusive device canbe manually placed into the introducer sheath by an operator by usingthe finger and thumb of one hand to pinch the device positioning unitinto the introducer sheath. Similarly, the vasoocclusive device can bemanually released from the introducer sheath by pinching the introducersheath to open the slot, and bending the introducer sheath to expose thedistal tip of the vasoocclusive device, which can then be stripped outof the introducer sheath along the length of the slot. However, suchmanual techniques of sheathing and unsheathing a vasoocclusive devicefrom the introducer sheath are highly dependent upon the manualdexterity of the operator. It would be desirable to improve theresheathing and unsheathing of a vasoocclusive device from such anintroducer sheath by providing a tool that will aid in the unsheathingand resheathing of the vasoocclusive device in such an introducersheath. The present invention satisfies these and other needs.

INVENTION SUMMARY

Briefly, and in general terms, the invention provides for a tool tofacilitate the unsheathing and resheathing of a vasoocclusive device,which includes a flexible pusher member and an embolic coil, in areloadable slotted introducer sheath. The resheathing tool is formedfrom a round tube that slides over the reloadable slotted introducersheath. The tubular resheathing tool advantageously includes an apertureapproximately at the middle of the tubular resheathing tool which aidsin the unsheathing of the vasoocclusive device from the reloadableslotted introducer sheath during introduction of the vasoocclusivedevice into a microcatheter for deployment of the vasoocclusive devicein treatment of a patient, and which aids in the resheathing of thevasoocclusive device in the reloadable slotted introducer sheath. Thetubular resheathing tool also provides a mechanism for locking thereloadable slotted introducer sheath and vasoocclusive device together.

The present invention accordingly provides for a resheathing tool havinga flexible tubular body with a wall, a central inner bore, proximal anddistal ends, and an aperture formed in the wall of the flexible tubularbody approximately midway between the proximal and distal ends of theflexible tubular body. In a presently preferred aspect, the aperture isformed as a slanted notch shaped aperture in one side of the flexibletubular body with a first slanted edge at a proximal end of the slantednotch shaped aperture extending from the exterior surface of theflexible tubular member distally, and inwardly to about half of thediameter of the flexible tubular member, and with a second transverseedge at a distal end of the slanted notch shaped aperture extendingapproximately perpendicular to the axis of the flexible tubular member,from the exterior surface to meet the distal end of the slanted edge.The slanted notch shaped aperture provides an oblique ramp on theslanted edge extending from the inner surface of the wall of theflexible tubular member to the outer surface of the wall of the flexibletubular member.

In the method of the invention, the tool can be used for progressivelyunsheathing an elongated vasoocclusive device from a reloadable slottedintroducer sheath by threading the reloadable slotted introducer sheathout through the aperture of the tool, while threading the elongatedvasoocclusive device distally toward a patient through the inner bore ofthe reloadable slotted introducer sheath, and sliding the resheathingtool distally toward the patient over the reloadable slotted introducersheath, to deliver the elongated vasoocclusive device through a deliverycatheter to a desired treatment target site in the vasculature of thepatient.

The tool can also be used to facilitate the resheathing of the elongatedvasoocclusive device in the reloadable slotted introducer sheath, byadvancing the tool proximally away from the patient over the reloadableslotted introducer sheath, which is received in the inner bore of thetool through the aperture of the tool, and over the elongatedvasoocclusive device which is received in the inner bore of the tool andpressed through the slot of the reloadable slotted introducer sheathinto the inner bore of the reloadable slotted introducer sheath.

Other features and advantages of the present invention will become moreapparent from the following detailed description of the preferredembodiments in conjunction with the accompanying drawings, whichillustrate, by way of example, the operation of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a prior artreloadable slotted introducer sheath for a vasoocclusive device.

FIG. 2 is a perspective view of a second embodiment of a prior artreloadable slotted introducer sheath for a vasoocclusive device.

FIG. 3 is a cross-sectional view of the prior art reloadable slottedintroducer sheath of FIG. 1.

FIG. 4 is a schematic diagram of the prior art reloadable slottedintroducer sheath to be used with the resheathing tool according to theinvention.

FIG. 5 is a longitudinal sectional view of the prior art reloadableslotted introducer sheath in combination with a vasoocclusive device,showing the advancing of the vasoocclusive device through the reloadableslotted introducer sheath.

FIG. 6 is a perspective view of the resheathing tool of the presentinvention.

FIG. 7 is a diagram of the resheathing tool of FIG. 6 showing thedisposition of a reloadable slotted introducer sheath and vasoocclusivedevice in the resheathing tool for purposes of unsheathing orresheathing the vasoocclusive device according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, which are provided for purposes ofillustration and by way of example, one example of a prior artreloadable slotted introducer sheath 10 for a therapeutic vasoocclusivedevice 12 is illustrated in FIGS. 1-5. The vasoocclusive devicetypically includes an assembly of an elongated flexible pusher member 14and an embolic coil 16 (only a portion of which is shown) attached tothe flexible pusher member, as illustrated in FIGS. 4 and 5. Theelongated flexible pusher member may, for example, include an elongatedoptical fiber having a distal end 18 sheathed in a tubular collar 20 ofshape memory material for retaining the embolic coil on the distal endof the flexible pusher member. The optical fiber can be sized to bequite flexible and bend sufficiently to follow the body lumen.Alternatively, the elongated flexible pusher member can be formed ofsuitable materials for conducting energy, such as radio frequencyenergy, magnetic energy, electrical energy, or ultrasonic energy, suchas an elongated metal member, for example, or of a heat pipe forconducting heat from a heat source. Alternatively, the flexible pushercan consist of a tubular or solid wire construction with attachment toan embolic coil to allow, for example, deployment by mechanical orhydraulic means.

Referring to FIGS. 1 and 3-5, the reloadable slotted introducer sheathis generally formed of a hollow, elongated tubular member 22 having anupper wall 24 and an opposing lower wall 26, opposing side walls 28 and30, and a longitudinal interior channel 32. The upper wall of theelongated tubular member includes a slot 34 or slit with opposinginterior sides 36 having surfaces extending through the upper wallleading to the interior channel, permitting introduction of thevasoocclusive device into the interior channel. The reloadable slottedintroducer sheath may have the exemplary dimensions illustrated in FIGS.3 and set forth in the table below. In the table, “A” indicates apossible longitudinal interior channel dimension (32) and “B” indicatesa possible outer diameter sheath dimension. System “A” (in.) “B” (in.)10 0.016 0.030 18 0.020 0.034

As is best seen in FIGS. 1 and 3 the upper wall of the elongated tubularmember adjacent to the slot typically has an outer angled or V-shapedconfiguration on the outside surface of the tubing, to facilitateloading of the vasoocclusive device into the reloadable slottedintroducer sheath. The slot may, for example, have opposing exteriorsurfaces forming an interior angle of about 110° to 150°. The lower wallof the tubing is typically about 0.002 to 0.004 inches thick to allowopposing sides of the slot of the hollow, elongated tubular member toflex outwardly to allow the slot to open to accept the vasoocclusivedevice. The configuration allows the flexible pusher member to beinserted into the reloadable slotted introducer sheath by positioningthe flexible pusher member and embolic coil assembly over the slot andproviding a sliding pressure, such as by a person's thumb, along thelength of the flexible pusher member and embolic coil assembly tointroduce the flexible pusher member and embolic coil assembly into thesheath. In this embodiment, the sheath is fully removable from theflexible pusher member.

FIG. 2 illustrates a second embodiment of a prior art reloadable slottedintroducer sheath 10′ for a therapeutic vasoocclusive device 12, whichtypically includes an assembly of a flexible pusher member 14 and anembolic coil 16, described above and illustrated in FIGS. 4 and 5. Thereloadable slotted introducer sheath 10′ is generally formed of ahollow, elongated tubular member 22′ having an upper wall 24′ and anopposing lower wall 26′, opposing side walls 28′ and 30′, and alongitudinal interior channel 32′. The upper wall of the elongatedtubular member includes a slot 34′ with opposing interior sides 36′having surfaces extending through the upper wall leading to the interiorchannel, permitting introduction of the vasoocclusive device into theinterior channel.

The upper wall of the elongated tubular member adjacent to the slottypically has an outer angled or V-shaped configuration on the outsidesurface of the tubing, to facilitate loading of the vasoocclusive deviceinto the reloadable slotted introducer sheath. The slot may, forexample, have opposing exterior surfaces forming an interior angle ofabout 110° to 150°. The lower wall of the tubing is typically about0.002 to 0.004 inches thick to allow opposing sides of the slot of thehollow, elongated tubular member to flex outwardly to allow the slot toopen to accept the vasoocclusive device. In this embodiment, the upperangled surface portions of the upper wall of the elongated tubularmember adjacent to the slot may be formed as outwardly extending wallsor wing members 38 to facilitate insertion of the flexible pusher memberand embolic coil assembly into the slotted sheath.

As is illustrated in FIGS. 4 and 5, a reloadable slotted introducersheath according to the invention receives an elongated vasoocclusivedevice that includes an assembly of the flexible pusher member 14 and anembolic coil 16, and that is adapted to be inserted into a portion of apatient's vasculature for occluding a portion of the vasculature for usein interventional therapy and vascular surgery. An unslotted segment 40of the reloadable slotted introducer sheath remains unslotted, such as asegment of length less than the unused working length of the pusher whenfully loaded into the microcatheter, for example, about 10 cm., so thatthe sheath can be pulled off of the vasoocclusive device along the slotas the vasoocclusive device is threaded through a delivery catheter forplacement of the embolic coil in the vasculature of the patient, untilthe segment of the reloadable slotted introducer sheath without a slotis reached. The unslotted segment of the reloadable slotted introducersheath is typically received in a rotating hemostatic valve 42, whichclamps the reloadable slotted introducer sheath, while allowing theelongated vasoocclusive device to slide through the sheath. The portionof the reloadable slotted introducer sheath threaded out through theaperture of the tool can be looped and left attached to the end of theflexible pusher member while the flexible pusher member is loaded into amicrocatheter (not shown). If the elongated vasoocclusive device isremoved without detachment and placement of the embolic coil, the sheathcan be loaded back onto the flexible pusher member starting at theconnected location by reversing the process and progressing toward anend of the flexible pusher member away from the patient. The sheath canbe advanced in this manner to cover substantially the entire elongatedvasoocclusive device to allow the vasoocclusive device to be advancedinto a microcatheter at a later time.

Referring to FIGS. 6 and 7, the present invention provides for aresheathing tool 50 to facilitate the unsheathing and resheathing of thecombination of a reloadable slotted introducer sheath 52 (shown in FIG.7), such as described above, and a vasoocclusive device 54 to bedisposed in the reloadable slotted introducer sheath. As describedabove, the vasoocclusive device typically includes a flexible pushermember and an embolic coil. The resheathing tool is typically formedfrom a round tube, and includes a flexible tubular body 56 with a wall58 and a central inner bore 60 that slides over the reloadable slottedintroducer sheath, a distal end 62 and a proximal end 64. The tubularresheathing tool advantageously includes an aperture 66 with an opening67 formed in the wall of the flexible tubular body approximately midwaybetween the proximal and distal ends of the flexible tubular body to aidin the unsheathing of the vasoocclusive device from the reloadableslotted introducer sheath during introduction of the vasoocclusivedevice into a microcatheter for deployment of the vasoocclusive devicein treatment of a patient, and sheathing or resheathing of thevasoocclusive device in the reloadable slotted introducer sheath, aswill be further explained below. When the reloadable slotted introducersheath and vasoocclusive device pass through the distal portion 69 ofthe resheathing tool, the tubular resheathing tool also serves to lockthe reloadable slotted introducer sheath and vasoocclusive devicetogether.

In a presently preferred aspect, the aperture is formed as a slantednotch shaped aperture in one side 68 of the flexible tubular body with afirst, slanted edge 70 that is slanted or oblique with respect to thelongitudinal axis 72 of the flexible tubular body at a proximal end 74of the slanted notch shaped aperture extending from the exterior surface76 of the flexible tubular member distally and inwardly to about half orslightly more of the diameter of the flexible tubular member, and with asecond, transverse edge 78 that is approximately perpendicular to thelongitudinal axis of the flexible tubular body at a distal end 80 of theslanted notch shaped aperture, extending from the exterior surface ofthe flexible tubular body to meet the distal end 82 of the slanted edge.The slanted notch shaped aperture provides an oblique ramp on theslanted edge.

As is illustrated in FIG. 7, in the method of the invention, theresheathing tool can be used in combination with a reloadable slottedintroducer sheath 52 and an elongated vasoocclusive device 54 toprogressively unsheathe and advance the elongated vasoocclusive devicethrough the inner bore of the resheathing tool and through the centralbore of the reloadable slotted introducer sheath by threading thereloadable slotted introducer sheath out through the aperture of thetool, and sliding the elongated vasoocclusive device through the innerbore of the reloadable slotted introducer sheath. While the resheathingtool slides distally toward the patient over the reloadable slottedintroducer sheath, the elongated vasoocclusive device can be pusheddistally toward the patient and slide through the reloadable slottedintroducer sheath even as the reloadable slotted introducer sheath isclamped by a rotating hemostatic valve, to be delivered to a target sitein the vasculature of the patient.

Similarly, the resheathing tool can be used in combination with areloadable slotted introducer sheath and an elongated vasoocclusivedevice to facilitate the resheathing of the vasoocclusive device in thereloadable slotted introducer sheath. Again referring to FIG. 7, tosheathe the vasoocclusive device in the reloadable slotted introducersheath, the elongated vasoocclusive device is introduced and advancedinto the inner bore of the flexible tubular body of the tool at aproximal end of the flexible tubular body of the tool as the tool slidesproximally along the reloadable slotted introducer sheath and elongatedvasoocclusive device away from the patient, and the reloadable slottedintroducer sheath is advanced into the inner bore of the flexibletubular body of the tool through the aperture of the tool, to press thevasoocclusive device through the longitudinal slot of the reloadableslotted introducer sheath into the inner bore of the reloadable slottedintroducer sheath. At the same time, the disposition of the reloadableslotted introducer sheath in the resheathing tool prevents the elongatedvasoocclusive device from moving out of the reloadable slottedintroducer sheath through the slot, locking the elongated vasoocclusivedevice in the reloadable slotted introducer sheath.

In each of the foregoing embodiments, the elongated tubular memberforming the reloadable slotted introducer sheath is typically formedfrom a thermoplastic material. The tubing may be formed from athermoplastic material such as high density polyethylene, for example.Alternatively, other similar polymeric materials may also be suitable,such as polyurethane, nylons, polyetheretherketone (PEEK),polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), andthe like.

It will be apparent from the foregoing that, while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

1. A tool to facilitate the unsheathing of a vasoocclusive device from areloadable slotted introducer sheath adapted to receive thevasoocclusive device, and to facilitate the resheathing of thevasoocclusive device in the reloadable slotted introducer sheath, thevasoocclusive device including an elongated flexible pusher member andan embolic coil connected to the elongated flexible pusher member, thetool comprising: a flexible tubular body including a wall, an innerbore, a proximal end and a distal end, the inner bore being adapted toslide over and receive the reloadable slotted introducer sheath and thevasoocclusive device; and an aperture formed in the wall of the flexibletubular body to aid in the unsheathing of the vasoocclusive device fromthe reloadable slotted introducer sheath for deployment of thevasoocclusive device in treatment of a patient, and to aid inresheathing of the vasoocclusive device into reloadable slottedintroducer sheath.
 2. The tool of claim 1, wherein said aperture isformed approximately midway between the proximal and distal ends of theflexible tubular body.
 3. The tool of claim 1, wherein said aperture isformed in one side of the flexible tubular body with a first, slantededge that is slanted with respect to a longitudinal axis of the flexibletubular body at a distal end of the aperture extending from the exteriorsurface of the flexible tubular member proximally and inwardly to abouthalf of the diameter of the flexible tubular member, and with a second,transverse edge that is approximately perpendicular to the longitudinalaxis of the flexible tubular body at a proximal end of the aperture,extending from the exterior surface of the flexible tubular body to meetthe proximal end of the slanted edge.
 4. The tool of claim 3, whereinsaid slanted edge provides an oblique ramp for the reloadable slottedintroducer sheath.
 5. A tool to facilitate the unsheathing of avasoocclusive device from a reloadable slotted introducer sheath adaptedto receive the vasoocclusive device, and to facilitate the resheathingof the vasoocclusive device in the reloadable slotted introducer sheath,the vasoocclusive device including an elongated flexible pusher memberand an embolic coil connected to the elongated flexible pusher member,the tool comprising: a flexible tubular body including a wall, an innerbore, a proximal end and a distal end, the inner bore being adapted toslide over and receive the reloadable slotted introducer sheath and thevasoocclusive device; and a slanted notch shaped aperture formed in thewall of the flexible tubular body to aid in the unsheathing of thevasoocclusive device from the reloadable slotted introducer sheath fordeployment of the vasoocclusive device in treatment of a patient, and toaid in resheathing of the vasoocclusive device into reloadable slottedintroducer sheath.
 6. The tool of claim 5, wherein said slanted notchshaped aperture is formed approximately midway between the proximal anddistal ends of the flexible tubular body.
 7. The tool of claim 5,wherein said slanted notch shaped aperture is formed in one side of theflexible tubular body with a first, slanted edge that is slanted withrespect to a longitudinal axis of the flexible tubular body at a distalend of the slanted notch shaped aperture extending from the exteriorsurface of the flexible tubular member proximally and inwardly to abouthalf of the diameter of the flexible tubular member, and with a second,transverse edge that is approximately perpendicular to the longitudinalaxis of the flexible tubular body at a proximal end of the slanted notchshaped aperture, extending from the exterior surface of the flexibletubular body to meet the proximal end of the slanted edge.
 8. The toolof claim 7, wherein said slanted edge provides an oblique ramp for thereloadable slotted introducer sheath.
 9. A method for facilitating thesheathing of a vasoocclusive device in a reloadable slotted introducersheath having a longitudinal slot and an inner bore, the vasoocclusivedevice having a proximal end and a distal end and including an elongatedflexible pusher member and an embolic coil connected to the elongatedflexible pusher member, the method comprising: providing a toolincluding a flexible tubular body having a wall with an aperture formedin the wall, an inner bore, a proximal end and a distal end, the innerbore being adapted to slide over and receive the reloadable slottedintroducer sheath and the vasoocclusive device; introducing a portion ofthe reloadable slotted introducer sheath through the aperture of thetool into the inner bore of the tool; introducing a portion of thevasoocclusive device into the inner bore of the tool adjacent to thelongitudinal slot of the reloadable slotted introducer sheath; andprogressively sliding the reloadable slotted introducer sheath throughthe aperture into the inner bore of the tool and sliding thevasoocclusive device through the inner bore of the tool to press thevasoocclusive device through the longitudinal slot of the reloadableslotted introducer sheath into the inner bore of the reloadable slottedintroducer sheath to thereby sheathe the vasoocclusive device in thereloadable slotted introducer sheath.
 10. A method for facilitating theunsheathing of a vasoocclusive device from a reloadable slottedintroducer sheath having a longitudinal slot and an inner bore, thevasoocclusive device having a proximal end and a distal end andincluding an elongated flexible pusher member and an embolic coilconnected to the elongated flexible pusher member, at least a portion ofthe vasoocclusive device being disposed within the reloadable slottedintroducer sheath, the method comprising: providing a tool including aflexible tubular body having a wall, an inner bore, a proximal end and adistal end, and an aperture formed in the wall, the inner bore of theflexible tubular body being adapted to slide over and receive thereloadable slotted introducer sheath and the vasoocclusive device;introducing the reloadable slotted introducer sheath and vasoocclusivedevice with at least a portion of the vasoocclusive device disposed inthe reloadable slotted introducer sheath into the inner bore of theflexible tubular body of the tool; advancing a proximal portion of thereloadable slotted introducer sheath and vasoocclusive device throughthe inner bore of the flexible tubular body of the tool; and advancingthe proximal portion of the reloadable slotted introducer sheath out theaperture while simultaneously advancing the vasoocclusive devicedistally through the inner bore of the tool and through the inner boreof the reloadable slotted introducer sheath.
 11. The method of claim 11,further comprising resheathing the vasoocclusive device in thereloadable slotted introducer sheath by the steps of: introducing aportion of the reloadable slotted introducer sheath through the apertureof the tool into the inner bore of the tool; introducing a portion ofthe vasoocclusive device into the inner bore of the tool adjacent to thelongitudinal slot of the reloadable slotted introducer sheath; andprogressively sliding the reloadable slotted introducer sheath throughthe aperture into the inner bore of the tool and sliding thevasoocclusive device through the inner bore of the tool to press thevasoocclusive device through the longitudinal slot of the reloadableslotted introducer sheath into the inner bore of the reloadable slottedintroducer sheath to thereby sheathe the vasoocclusive device in thereloadable slotted introducer sheath.